When a patient is medicated with a liquid medicament such as a narcotic, a sedative and a cardiotonic over a long time m an operating room or an intensive care unit of a hospital, the liquid medicaments are administered little by little to the patient from a syringe by using a syringe pump under a predetermined administration rate. While monitoring a patient's state or an electrocardiogram etc., medical doctors such as an operating surgeon and an anesthetist or a clinical engineer under the medical doctor's directives control the dose and an administration rate suitably so that the liquid medicament is optimally administered.
In such cases, the following medical malpractices have been reported not a little every year. For example, a medicament other than a prescription was incorrectly prepared in a syringe and administered to a patient, incorrect dosage of a prescription was administered, or incorrect drive conditions of a syringe pump were mistakenly set for dose and administration role which should be appropriate during an operation or treatment.
In medical practices, measures against such a human error, are taken. For example, medical doctors or nurses in medical practices reconfirm a label of an ampule accommodating pharmaceutical ingredients before or during preparation of a liquid medicament. And they directly fill out administration information such as a name of a medicament, a dose or a concentration thereof, and an administration rate thereof onto a syringe or a label attached thereon, before or after preparation of the liquid medicament for administration from the ampule. Furthermore, during the administration, they repeatedly check the name of the medicament, the dose thereof, the concentration thereof, the administration rate, the repetition of the administration and the integrated amount of the administration, the remained amount of the medicament etc. Thus, a number of items are checked several times so that a human error may not happen before and during the operation, and during the treatment.
Patent Document 1 discloses a medical container such as a transparent prefilled syringe as below. The medical container comprises a first volume-measurement means indicating a volume of content therein, which is provided on one side of wall portions facing each other in the medical container so as to be directly viewable, and a second volume-measurement means indicating a volume of the contents therein, which is provided on another side of the wall portions lacing each other in the medical container so as to be viewable through the one side of the wall portions. And a writable label, in which data writing parts are disposed, is stuck on the medical container.
Even if two or more of such checks are performed, there are still some of the following problems. For example, a number of the syringes set on plural syringe pumps are mutually confusing because the syringes are put in parallel in the operating room or the intensive care unit. Furthermore, if the amount of the liquid medicament to be administered such as the anesthetic etc. is small, it is hard to visually check the administration status for each syringe in one glance by the operating surgeons by the lying patient in the operating room, the anesthetist or the clinical engineer who optimize the anesthetized state near the foot of the patient, or a attending physician who treats the patient in the intensive care unit, because the syringe is too small and the administration information of terms written on the syringe or in the label thereon is too small. Moreover, when the administration information is directly written down on a syringe, the information should be written by using a pen of an oil-based ink because the syringe is made from non-polar plastics such as a cycloolefin resin and a polypropylene resin. And since the syringe is cylindrical, it is hard to write down legible and clear words of the administration information on syringe or in the label thereon. Likewise, the administration information marginally written on the syringe or in the label thereon may be visually distorted due to a bent surface of the syringe having a cylindrical shape. It is also hard to visually check the terms of the information which are unexpectedly located at an upper or lower side or a back side of the cylindrical shape of the syringe. Additionally, when the terms are written thereon, it is hard to check residual quantity of the liquid medicament because graduations disposed on a surface of the syringe may be unreadable.
Preventive actions for elimination of human errors such as error concerning use of medical appliances or medical equipments are referred to as so-called human factor engineering. The design through the human factor engineering is becoming a de facto standard for manufacture or approval requests of the medical appliances or the medical equipments. However syringes for administration by using a syringe pump have not been put into practical use according to effective human factor engineering yet.